Since the past, nitrile rubber (acrylonitrile-butadiene copolymer rubber) has been used as a material for hoses, tubes, and other automotive use rubber parts by making use of its fuel oil resistance, mechanical properties, chemical resistance, etc. Further, hydrogenated nitrile rubber (highly saturated nitrile rubber) which is obtained by hydrogenating the carbon-carbon double bonds in the polymer main chain of nitrile rubber is further excellent in heat resistance, so is being used for belts, hoses, seals, gaskets, diaphragms, and other rubber parts.
In recent years, the demands for the properties of automobile use rubber parts have become severe. In belts, hoses, seals, gaskets, diaphragms, and other rubber parts, further improvements are being sought in the normal physical properties, oil resistance, fuel oil resistance, tensile strength under a high temperature etc.
In this situation, Patent Document 1 discloses a rubber composition which comprises a hydrogenated NBR elastomer matrix in which microparticles comprised of Nylon are present dispersed and contains a functional group-containing ethylene-based copolymer. According to the rubber composition which is described in this Patent Document 1, while cross-linked articles which have appropriately improved normal physical properties are obtained, but there is the problem that the rollability (wrapability on the roll) is poor and the problem that the oil resistance, fuel oil resistance, and tensile strength under a high temperature are inferior.